Ensure user trap code 0 is never used #1054

Job	Run time
abi_cafe (macos-latest, aarch64-apple-darwin)	2m 49s
abi_cafe (macos-latest, x86_64-apple-darwin)	14m 16s
abi_cafe (ubuntu-latest, x86_64-unknown-linux-gnu)	3m 6s
abi_cafe (windows-latest, x86_64-pc-windows-msvc)	5m 54s
	26m 5s

Provide feedback